Biology Final Review

Topics: DNA, Cell, Eukaryote Pages: 48 (17056 words) Published: April 7, 2013
BSC2011C Final Review Unit 1 Review Ch. 25, 22, 23, 24, 26, 19, 27 Ch. 25 1. Life is metabolism and heredity. Metabolism is the mechanism that creates order and complexity from chaos, by acquiring and expending energy. Heredity is the ability of an organism to copy itself and it is broken down into: i. Multiplication, ii. Inheritance, iii. Variation. 2. DNA codes via RNA for 20 of naturally occurring amino acids. Amino Acids are the building blocks of proteins and bodies. DNA stores and transmits hereditary information, but proteins do most of the work. DNA IS THE UNIVERSAL DIGITAL CODE FOR LIFE. To replicate and synthesize proteins, DNA relies on the pre-existence of protein molecules and RNA molecules. 3. RNA is the bridge between DNA and proteins, via mRNA for transcription and rRNA for translation. Thus, RNA can survive on its own while DNA relies on the existence of RNA and proteins, with them DNA is helpless. 4. The 4 points of “first life” are: 1. The Abiotic (non-living) synthesis of small organic molecules, such as amino acids and nucleotides. 2. The joining of these small molecules into macromolecules, including proteins and nucleic acids. 3. The packing of these molecules into “protobionts,” droplets with membranes hat maintained an internal chemistry different from that of their surroundings. 4. The origin of self-replicating molecules that eventually made inheritance possible. 5. The first cells to develop occurred in this order: Monomers > Polymers > Protobionts > RNA ‘world’ > DNA protobionts > first cell. 6. Fossils are the evidence of life and evolution. Organisms trapped in sediment > remain mineralized with hard and soft parts. 7. Fossils can be dated by two methods: Radiometric dating & Magnetism. In Radiometric dating, the age is based on the decay of radioactive isotopes. A radioactive “parent” isotope decays to a “daughter” isotope at a constant rate. The rate of decay is expressed by the half-life, the time requires for 50% of the parent isotope to decay. In Magnetism, the formation of volcanic and sedimentary rocks, iron particle in the rock align themselves with Earth’s magnetic field. 8. The fossil record is based primarily on the sequence in which fossils have accumulated in sedimentary rock layers called “strata.” 9. The first two eons – the Archaean and the Proterozoic – together lasted approximately 4 billion years. The Phanerozoic eon, has last roughly the last half billion years, and encompasses most of the time hat animals have existed on Earth.

10. Early prokaryotes were Earth’s sole inhabitants from at least 3.5 BYA – 2.1 BYA. Atmospheric O2 increased gradually from 2.7-2.2 BYA, but shot up rapidly to more than 10% of its present level. The first eukaryotes began to appear about 2.1 BYA, multicellular eukaryotes evolving around 1.5 BYA. Many living animals appeared during the Cambrian period which was approximately 535-525 MYA. 11. The order of time is three eons which have last approximately 4.6 billion years. The order is Eons > Era > Period > Epoch. 12. Methods in which parokaryotes derived energy: Autotrophs (synthesize needed organic molecules), Chemotrophs (energy from sulfur or methane), Photoautotrophs (photosynthesize to split water and liberate O2 generating energy). 13. Life falls into three domains: Eukarya, Archaea, Bacteria 14. Anaerobic respiration: 1 glucose + 2 water  Aerobic respiration: 1 glucose + 6 oxygen  1 lactic acid + 2 ATP 6 C02 + 6 H20 + ca. 30 ATP

15. Small prokaryotes enter host as (undigested) prey or parasitesHost & invader gain mutual advantages (e.g. energy from mitochondrial ancestors) Host & endosymbionts become single organism. The evidence for this is: Organelle structure & biochemistry homologous to living prokaryotes (e.g. homologous electron transport mechanisms). Organelle replicates by binary fission, as do prokaryotes. Organelles possess their own DNA which, as in prokaryotes contains a single, circular DNA molecule with little...
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